Articulated railway freight trains and trucks which utilise containers for carriage of bulk materials (such as mineral ores, grains and the like) are known. In rail applications, the bulk materials container can be seated on an elongate wagon undercarriage which itself is connected to two bogies located near either end of the wagon undercarriage. The bogies includes wheel sets and a bolster to which the wagon undercarriage is mounted via an articulated connection or centreplate device. The articulated connection is provided by mating a male member of the under frame and a female component of the bogie bolster.
The aim in railway freight wagon design is to maximise the weight of material to be carried by the wagon and also to maximise the gross to tare ratio (total weight of loaded wagon compared with the weight of the wagon when empty). If the weight of a railway wagon itself can be minimised, the weight of bulk material to be carried in the wagon can be increased, for a given total load limit on a railway line structure. Such considerations can determine whether a railway wagon design is economically suitable for a particular purpose. Therefore great emphasis is placed on the development of lightweight freight wagon componentry.
In an effort to reduce the weight of a bulk material container, one known method is to reduce the thickness of the container side walls. However, if the side walls of the bulk material container portion of a railway wagon are made too thin, this can lead to outward deformation of the walls when the wagon is loaded with particular bulk materials. The wagon can become stuck in loading facilities or in tunnels etc when overloaded in this manner. Furthermore, if deformed in this way, the walls can become severely stressed when the wagon is in motion and may even buckle or burst, with catastrophic results.